Cancer vaccines made from autologous cell preparations are based on the well established fact that tumor cells bear specific neo-antigens. The immunogenicity of cancer cells is too weak to elicit a pronounced immune reaction capable of coping with tumor development in cancer patients. Also artificial coupling of such tumor cells with strong antigens failed to give adequate results.
Since 1976 the "vertical displacement" approach, Borochov et Shinitzky, Proc. Nat. Acad. Sci., U.S.A. 73, 4526-30 (1976) has been used to enhance the immunogenicity of tumor cells. Increase of membrane lipid microvisocosity results in an exposure of latent antigens which render the system more immunogenic. It has been shown that rigidification of the membrane by incorporation of cholesteryl hemisuccinate (CHS) enhances the exposure of the effective antigens and that such cells can be used with a greater degree of success for immunization of mice against certain tumors, Shinitzky et al., Proc. Natl. Acad. Sci. U.S.A. 76 5313-5316 (1979). This provides a potential anti-tumor vaccine.
The clinical potential of these findings was examined by delayed type hypersensitivity reaction (skin-test) in patients with solid tumors against their autologous irradiated tumor cells. Only upon enrichment with CHS a strong response could be detected, Skornick et al. Cancer Immunolo. Immunother. 11, 93-96 (1981).
The vertical displacement of proteins was used to shed off blood group antigens of human erythrocytes, Muller and Shinitzky, Exp. Cell Res. 136, 53-62 (1981). This illustrates that by the combination of CHS and hydrostatic pressure it is possible to isolate surface proteins without the use of detergents which are undesired as they tend to denature such proteins.